1. Field
Embodiments of the present disclosure relate to a washing machine having an outer tub, a spin basket rotatably installed in the outer tub, and a balancing device mounted to the spin basket.
2. Description of the Related Art
Conventionally, a washing machine having an outer tub and a spin basket rotatably installed in the outer tub to perform washing, rinsing and drying of laundry such as clothing accommodated in the spin basket has been known.
The conventional washing machine is subjected to vibration when the spin basket having laundry accommodated therein rotates to perform drying operation. This vibration mainly results from uneven distribution of the laundry accommodated in the spin basket. Accordingly, a ball balancer to damp the vibration is mounted to the spin basket.
Specifically, the ball balancer is formed in a ring shape, and is provided with a plurality of balancing balls accommodated in an accommodation chamber and viscous fluid. The balancing balls and viscous fluid are allowed to move in the accommodation chamber in the circumferential direction of the accommodation chamber. The balancing balls are submerged in the viscous fluid and thus movement thereof is limited to an extent. Thereby, self-excited vibration of the balancing balls revolving in the accommodation chamber may be restricted. During rotation of the spin basket, the balancing balls are moved in the accommodation chamber in the circumferential direction by centrifugal force and finally positioned at the side opposite to the maldistributed laundry. As a result, balanced rotation of the spin basket is maintained by the weight of the balancing balls.
In the case that the positioned balancing balls fail to perform balancing during stoppage of rotation of the spin basket before start of the drying operation, the maldistribution of the balancing balls causes variation in magnitude of horizontal vibration (rocking rotation) of the spin basket while the rate of rotation of the spin basket crosses a first resonance section. If the horizontal vibration of the spin basket is large, the outer tub may collide with the outer casing. In addition, when the outer tub collides with the outer casing, control is generally performed to force the drying operation to be terminated. This may waste energy and time.
In the case of the conventional washing machine, a recessed accommodation portion to accommodate the balancing balls is formed on the bottom surface of the accommodation chamber. Thereby, unbalanced positioning of the balancing balls before start of the drying operation of the washing machine is resolved. Accordingly, when the rate of rotation of the spin basket passes the first resonance section, variation of the horizontal vibration of the spin basket due to maldistribution of the balancing balls may be suppressed.
However, the conventional washing machine has a viscous fluid accommodated in the accommodation chamber. Thereby, movement of the balancing balls may be restricted by the viscous resistance of the viscous fluid, and thus it may be difficult to accommodate the balancing balls in the recessed accommodation portion.
In this regard, a control operation may be performed to decelerate or accelerate rotation of the spin basket to move the balancing balls to positions where weight balance is formed between the balancing balls and the viscous fluid.
However, this control may take energy and time.